1. Field of the Invention
The present invention relates to an improved catheter having a catheter body comprising a coil body, as well as a method of producing such catheter in a favorable manner.
2. Description of the Related Art
Catheters have been known as medical apparatuses that are used via insertion into blood vessels, gastrointestinal tracts, urinary tracts and other tubular organs and tissues of humans. As one type of these catheters, those having its main body, or part inserted into the human body, comprising a coil body formed by winding or stranding long, thin round metal wires are known (such as the one disclosed in Japanese Patent Laid-open Publication No. 2004-242973). For example, these catheters are favorably used in procedures that are performed to dilate an occluded area in a blood vessel.
Specifically, when performing a procedure using one of these catheters having a coil body as the catheter body, generally a guide wire is inserted into the occluded area. Then, the coil body is guided by the guide wire into the occluded area. The coil body dilates the occluded area and forms a somewhat large channel in the occluded area. Next, a relatively small balloon catheter is inserted into the aforementioned channel, after which the balloon is inflated to expand the occluded area further. After this process, a larger balloon catheter may be inserted and inflated, if necessary, to expand the occluded area further. This ensures a sufficient blood flow through the applicable blood vessel.
In these procedures, the aforementioned catheters exhibits excellent operation performance in blood vessels based on the sufficient flexibility and good torque transmissibility of their coil bodies. This is why the bodies of these catheters can be smoothly inserted into blood vessels without damaging the interior walls of the blood vessels. These catheter bodies also allow an occluded area to be dilated in a reliable, easy manner to a sufficient size at which a balloon catheter can be inserted.